July 25, 2021

Preserved some cellular functions in brains of pigs four hours after his death | Science

Preserved some cellular functions in brains of pigs four hours after his death | Science



A team of scientists has managed to preserve some basic cellular functions in the brains of dead pigs. Despite the achievement, there was no evidence that the brain cells recovered the necessary electrical function for the brain to function again.

The scientists developed a brain perfusion system that mimics blood flow after death and maintains it at body temperature. They tested it on the brains of 32 decapitated pigs in a slaughterhouse, four hours after the animals died. After six hours of perfusion, the researchers detected a reduction in brain death and the restoration of some basic functions at the molecular and cellular level, including the functioning of some neuronal connections. Despite this, there was no sign of functioning at a global level, as described by the neuroscientist's team Nenad Sestan, from the Yale School of Medicine (USA), in a study published today in the scientific journal Nature.

The research suggests a possible future pathway to preserve the brain tissue of mammals after the oxygen flow stops after the heart stops. The authors themselves acknowledge that they still do not know if it would be possible in the future to recover normal brain activity and that more studies are needed to determine it.

The research suggests a future way to preserve the brain tissue of mammals after cardiac arrest

"This work opens the door to stop the brain deterioration that leads to death, because until now it was thought that about four minutes after death there was irreversible damage," he says. Juan Lerma, researcher at the Institute of Neurosciences of Alicante. "It is a very invasive experimental method, because it replaces the blood with an artificial fluid, and it remains to be proven that this brain can return to life and be reconnected with the body," he points out.

The finding may have implications in cases of organ donation, because it suggests that the deterioration of the brain after the death of animals is slower than previously thought.

"The advance here is that, with the right technology, we could now have more time to recover some molecular, cellular and microvascular functions before they are completely compromised" in pigs, "a perspective that could one day extend time potential to carry out restoration interventions in human tissues, "said the neuroscientist Martin Monti, from the University of California at Los Angeles, to the specialized portal Science Media Center.

"Although the results are exciting, the animals remained in a state of absolute neuronal silence, which is a basic criterion for considering brain death. Secondly, given that these results say very little about the possibility of undoing the neuronal silence once it has taken over the brain, they say even less about the possibility of recovering any aspect of cognitive function and consciousness, "he explains.

Although the results are exciting, the animals remained in a state of absolute neuronal silence "

"It is also unknown if this result in pigs will one day translate into an application in humans, so for now, the cautious interpretation of this work is that, with this technology, the window of time to rescue from the death process a deeply damaged neuronal tissue of a pig could be wider than we thought, "Monti adds.

"This research shows that pig brain cells can retain some of their basic functions hours after death, provided the brain receives artificial blood flow. But the authors have not seen any evidence of the kind of brain activity necessary for perception and thinking. For neuroscientists, this study is important because it provides another tool to study the brain, "he said. Tara Spiers-Jones, neuroscientist at the University of Edinburgh.

Other experts are also very cautious. "The study takes up an observation that already 50 years ago attracted considerable attention from the international press. Then, it could be demonstrated for the first time in animal experiments that the brain of cats and monkeys could be reactivated after a full circulatory stoppage of one hour and that nerve cells do not die after eight or ten minutes, as is still often assumed nowadays, "said the German neurologist Konstantin Alexander Hossmann, former director of the Max-Planck Institute for Metabolic Research, the Science Media Center.

"This new research confirms this finding in pigs and suggests that brain resuscitation may be possible four hours after the onset of circulatory arrest. However, the prerequisite, then and now, is that the brain is completely perfused with oxygen and the nutrients necessary for brain metabolism from the start of the resuscitation attempt, "warns Hossmann. "It remains to be seen if this method can also be used in a resuscitation [humana]"He says.

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